A wireless base station is used together with a radio antenna in a mobile communication to communicate with a mobile station or hand-held phone. For example, in a wireless telephone system, the signals from one or more of the mobile telephones in an area are received at a nearby base station. The base station connects the call to the backbone of the network over a fixed line or by radio transmission.
Modern radio antennas include a number of antenna line devices that are used to control and monitor various aspects of the radio antenna. It is easy for a single base station to send control signals to the antenna line device (ALD) in the radio antenna. Issues arise, however, when a number of base stations or similar devices, such as but not limited to a node B, are co-located and wish to send control signals to a multi band radio antenna with a plurality of subunit ALDs. This plurality of ALDs is addressed through a single control interface, in accordance with the AISG (Antenna Interface Standard Group) standard. International patent application WO 2010/133352 (Kathrein) teaches, for example, such a system in which each one of the antenna line devices can communicate bi-directionally over a common external communications bus with a remote control unit. The multi-band radio antenna disclosed in this specification cannot be addressed by multiple base stations or Node Bs.
German patent application No. DE 10 2011 015 551 (Kathrein) teaches a system in which a so-called site sharing adapter is used to communicate the control signals to one or more of the antenna line devices using carrier signals at different frequencies for different ones of the base stations.
European Patent No. EP 2 340 683 (Kathrein) also teaches a system in which multiple base stations occupying a single site. The base stations are connected to a plurality of antennas, including ALDs, for the transmission of radio signals using the corresponding protocols. The ALDs can be addressed by various base stations and the ALD control signals are decoupled from each other by multiplexing.
European Patent No. EP 2 469 790 (Huawei) discloses a method and system for transmitting radio signals. The method comprises receiving AISG protocol signals sent by one or more local devices and adding labels to the AISG protocol signals. These labels are used to identify mapping relationships between the antenna line devices and the base station. The AISG protocol signals from the internal line devices are combined together in a data packet and sent to an adapter through a shared field.
Kathrein Werke had also sold a tower-mounted amplifier under product reference DTMA-1800-UMTS-12-AISG. This tower-mounted amplifier (TMA) receives the signals from one of the base station and passes the signals directly through to a remote electrical tilt device.
Korean Patent No. KR 20070063660 (SK Telecom) discloses an apparatus for sharing an antenna feeding line. The apparatus includes a base station device comprising transmission and reception units, antennas, and a two frequency transformers. A common feeding line is used from each of the transmission and reception units to the antennas. A first frequency transformer transforms a signal of a plurality of transmission and reception units to a signal of a different frequency band, and transmits the transformed signal to the antennas through the common feeding line. The second frequency transformer reproduces a signal having an original frequency band, and outputs through a plurality of outputs the reproduced signal to the antennas.